Afghanistan said on Sunday it had discovered an oilfield with an estimated 1.8 billion barrels in the north of the war-ravaged country, where U.S. and other foreign forces are trying to tame a Taliban-led insurgency.

The discovery of the basin between northern Balkh and Shiberghan provinces was made after a survey conducted by Afghan and international geologists, said Jawad Omar, a spokesman for the ministry of mines.

“I do not know its price in the market. But the initial survey says there are 1.8 billion barrels of oil and I think there will be more than what it is estimated,” he told Reuters.

General David Petraeus said the July 2011 deadline for the withdrawal of troops from Afghanistan is “conditions based” and could change depending on his assessment of progress.

“This is a date when a process begins, that is conditions based,” Petraeus said in an interview on NBC’s “Meet the Press” program. “And as the conditions permit we transition tasks to our Afghan counterparts and the security forces and in various governmental institutions and that enables a, quote, responsible drawdown of our forces.”

Petraeus is leading a force of 142,000 U.S. and North Atlantic Treaty Organization troops who are in the midst of an offensive to try to push the Taliban out of their stronghold in Kandahar Province in southern Afghanistan. Petraeus has held the command for less than two months after replacing General Stanley McChrystal on June 30.